Is your doctor competent enough to get the dietician to incorporate these into the diet protocol at the hospital and your take home diet protocol and the gift shop and vending machines? NO? So, your doctor failed at that task! What are YOU going to do about that incompetence? Let it pass? Or pay it forward and get someone competent in the hospital for the next stroke survivor?
5 worst foods for your brain, according to dietitians
Sure, living longer is a goal most of us share. But it's not just about the number of candles on the birthday cake — the quality of those years matters just as much. And when it comes to living well into your 70s, 80s and beyond, brain health is key.
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The numbers are striking: according to the Alzheimer's Association, more than 7 million U.S. adults have Alzheimer's, and that number is projected to reach 13 million by 2050. Perhaps even more surprising, 1 in 3 older adults dies from Alzheimer's — more than breast and prostate cancer combined.
The good news? Nearly 45% of dementia cases may be preventable or delayed through lifestyle changes, and diet is one of the biggest factors.
The MIND diet (a.k.a. Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay) caught my attention back in 2015, and I've followed the research closely ever since. Developed specifically to help prevent and slow the progression of Alzheimer's and other forms of dementia, it identifies foods that are particularly beneficial for brain health — and five to avoid. The broader research agrees: it's your overall dietary pattern, along with lifestyle factors like exercise, sleep and social connection, that really moves the needle on brain health.
That said, certain foods consistently stand out as particularly harmful. After talking with four fellow dietitians, these five kept coming up.
Sweetened beverages
Gretchen Terry-Leonard, host of the Your Second Prime Podcast and author of Your Second Prime: Does Aging Suck, or Do We Suck at Aging?, puts sugary beverages at the top of her list — and it's not hard to see why. Soda, energy drinks and sweetened iced coffee drinks are low in (or completely devoid of) essential nutrients like fiber, vitamins and minerals, while typically packing a full day's worth of added sugar, if not more. As she puts it, "liquid sugar hits the bloodstream fast, and the brain takes that hit harder than most organs."
The effects show up in the short term and the long term. Blood sugar spikes and crashes are linked to brain fog, poor attention and reduced processing speed — if you've ever eaten one too many donuts at lunch, you've probably felt this firsthand. Over time, chronically high sugar intake — particularly fructose, found in soda and many packaged foods — has been associated with impaired memory formation and changes in the hippocampus, the brain's primary memory center. High sugar diets are also consistently correlated with higher dementia rates, partly because excess added sugar is pro-inflammatory and raises the risk of obesity and type 2 diabetes — known risk factors for Alzheimer's.
And then there's the gut-brain connection, notes Terry-Leonard. High sugar intake disrupts the gut microbiome, and while that research is still evolving, the link between gut health and brain health is becoming increasingly hard to ignore.
Deli meats
Another food on Terry-Leonard's radar — and one that came up repeatedly among our experts? Deli meats, along with other processed meats like hot dogs and salami. Sorry, charcuterie board fans.
"The World Health Organization classified processed meat as a Group 1 carcinogen for colorectal cancer back in 2015, and the brain research has been catching up," explains Terry-Leonard. "Ultra-processed meat has been associated with faster declines in executive function and global cognition in older adults, and a 2024 French dementia study found that delicatessen meats were one of the main dietary vehicles for a small group of neurotoxic chemical contaminants tied to higher dementia risk."
That doesn't mean you have to swear off the charcuterie board entirely, though. Terry-Leonard's advice: think like the Mediterranean. "Let the plant side carry the board — olives, marinated vegetables, fruit, nuts — with the meat as a flavor accent rather than the main event."
Jennifer Ventrelle, MS, RDN, assistant professor in the Departments of Family and Preventive Medicine & Clinical Nutrition at Rush University Medical Center, echoes this approach. The MIND diet doesn't ban these foods outright — it frames them as foods to limit, not avoid. The target is keeping processed meat to 3- to 5-ounce portions, no more than once per week.
Ultra-processed foods
Potato chips, packaged sweets, instant noodles, frozen dinners — if it comes in a bag or box with an ingredient list that reads like a chemistry exam, it probably falls into the ultra-processed category. And experts broadly agree that limiting these foods is one of the more impactful things you can do for your brain.
"Ultra-processed foods tend to be low in fiber and micronutrients while being high in refined carbohydrates, unhealthy fats and additives," explains Johannah Katz, registered dietitian at Consumer Health Digest. "That combination is pro-inflammatory and can contribute to blood sugar dysregulation — both of which can impact cognitive function and mental health."
The research is pretty sobering. A 2022 study published in JAMA Neurology followed 10,775 individuals over eight years. Those who ate the most ultra-processed foods had a 25% faster rate of executive function decline and a 28% faster rate of overall cognitive decline compared with those who ate the least.
The effects extend beyond cognition too. "Ultra-processed foods have also been linked to poorer mood and higher rates of depression," notes Ventrelle. A 2023 analysis of over 31,000 women found that those who consumed nine or more servings of ultra-processed foods per day were 50% more likely to develop depression.
And it's not just what these foods contain — it's what they're missing. They tend to be low in the fiber, omega-3 fatty acids, polyphenols and other nutrients that actively support brain health. Both Ventrelle and Terry-Leonard also flag the gut microbiome angle: strip out the fiber and beneficial compounds that real food carries, and you're essentially starving the good gut bacteria that communicate directly with your brain — while feeding the bad ones.
The good news is that small shifts add up. Swapping ultra-processed snacks for healthier options or whole food alternatives — nuts instead of chips, fresh fruit instead of packaged sweets, whole grains instead of instant noodles — gives your brain the nutrients it's actually looking for.
Fried foods
It's probably no surprise that fried foods aren't great for your heart. But their impact on your brain? That part tends to fly under the radar.
The connection starts with the oils. Many fried foods are cooked in oils high in saturated fat or even partially hydrogenated oils, which contain industrial trans fats. "These are still tucked into some fast food fryers and shelf-stable baked goods," notes Terry-Leonard. These fats raise LDL cholesterol, contribute to arterial inflammation and reduce blood flow — and when blood flow to the brain is compromised, so is cognitive function.
Then there's what happens to the food itself during deep-frying. A U.K. Biobank study of more than 140,000 people found that eating just one serving of fried food per day was associated with a 12% higher risk of anxiety and a 7% higher risk of depression. The culprit is acrylamide — a chemical formed during the frying process that's been shown to contribute to neuroinflammation and weaken the blood-brain barrier, making the brain more susceptible to damage over time.
These findings align with the MIND diet, which Ventrelle recommends following: keep fried foods to less than one serving once per week.
Alcohol
Alcohol is a tricky one. After all, both the MIND diet and the Mediterranean diet allow for up to one 5-ounce glass of wine per day. But the science has shifted. "This one is a bit more controversial lately," notes Ventrelle, "as there have been some studies suggesting that some individuals should not consume any alcohol at all for heart health" — and increasingly, brain health too.
Here's what we know: any amount of alcohol affects the central nervous system by disrupting neurotransmitters. It suppresses glutamate, which plays a key role in memory and cognition, and boosts GABA, which slows brain activity. In the short term, this shows up as impaired balance, speech, reasoning and impulse control. Heavy drinking can also cause blackouts — episodes in which the hippocampus is temporarily unable to form new long-term memories.
The longer-term picture, though, is particularly concerning. Regular alcohol consumption has been linked to reduced brain volume, and even one drink per day has been linked to measurable shrinkage. A 2022 study of 36,678 generally healthy middle-aged and older adults found that the more people drank, the greater the damage — with heavy drinkers (four or more drinks per day) showing brain volumes that appeared roughly 10 years older than those of non-drinkers.
Foods to focus on instead
So what should you eat? Ashley Koff, RD, nutrition course director at the University of California, Irvine and author of Your Best Shot, recommends focusing on a variety of colorful produce and low-mercury fatty fish.
Ventrelle and Terry-Leonard both point to the MIND diet as a helpful framework. In the Rush Memory and Aging Project, people with the highest adherence to it had cognitive decline rates equivalent to being seven and a half years younger — a finding that's hard to ignore. The diet specifically promotes these foods for their brain health benefits:
Leafy green vegetables
Other colorful vegetables
Berries
Nuts and seeds
Fish and seafood
Poultry
Whole grains
Beans and legumes
Terry-Leonard adds one more category worth incorporating: fermented foods like yogurt, kefir and sauerkraut that provide probiotics to promote gut health.
FAQs
What foods are linked to dementia?
Diets high in added sugar, sugar-sweetened beverages, ultra-processed foods, processed meats and alcohol have all been linked to increased dementia risk. On the flip side, the MIND diet — which emphasizes leafy greens, berries, olive oil, nuts, fish and whole grains — remains the most rigorously studied dietary pattern for dementia prevention.
Why are processed foods unhealthy?
Ultra-processed foods are typically high in added sugar, sodium, refined carbohydrates and unhealthy fats while being low in key nutrients like fiber, omega-3 fatty acids, vitamins and minerals. For brain health specifically, that combination is pro-inflammatory, disrupts blood sugar regulation and starves the gut bacteria that communicate directly with your brain.
Meet our experts
Gretchen Terry-Leonard, host of the Your Second Prime Podcast and author of Your Second Prime: Does Aging Suck, or Do We Suck at Aging?
Jennifer Ventrelle, MS, RDN, assistant professor in the Departments of Family and Preventive Medicine & Clinical Nutrition at Rush University Medical Center
Johannah Katz, registered dietitian at Consumer Health Digest
Ashley Koff, RD, nutrition course director at the University of California, Irvine and author of Your Best Shot.
Our health content is for informational purposes only and is not intended as professional medical advice. Consult a medical professional on questions about your health.
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